Status of subdomains

How are subdomains perceived by Google (and Yahoo, MSN)

[tigertom]

Are subdomains perceived as part of the 'mother' domain, or as separate sites?

I know there was a surge of subdomain spam a year or so ago, and I was wondering what the current status was.

If you use them, can you rank well with them, or will they be penalised in favour of the mother domain, or just because they are subdomains?

Thank you.

[tigertom]

Having researched this on this forum, and one other, the consensus appears to be that:

They are counted as separate domains.

[tedster]

I would say subdomains are scored "almost" as separate domains - there are some crossover areas. For example, a subdomain can occur in the set of SiteLinks [webmasterworld.com] - those extended listings that Google sometimes adds to a #1 result for the main domain.

The key to subdomain success is to establish any subdomain for a discrete purpose, separate from the main domain -- and then develop it in the way you would develop any separate domain. That means maintain, refresh, avoid duplicating content, no excessive cross-linking and so on. If the purpose is not that solid, then the content probably shouldn't be a subdomain.

[lakr]

Yep, thank you Tedser, you Did have a proper Answer for my question.

The content for each subdomain is very unique, except the navigation, it is the same as the domain.com.

Currently, I feel that this does not pose any problems because those subdomains still have high ranking on Google, but in the long term I have to change it as soon as possible.

Google causes me so many headaches.

Thanks,

Lkr